Sequential wet extraction of phosphorus from sewage sludge using alum sludge: reassessing the aluminium-phosphorus speciation using experimental and simulation approach
Sewage sludge (SS) is a reclaimable phosphorus (P) source for fertilizer production, but it has a high toxic trace element (TE) concentration. Using alkaline leaching of SS, P can be extracted without simultaneous extraction of TEs. However, low P recovery efficiency during alkaline leaching is a ma...
| Main Authors: | , , , , , , , |
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| Other Authors: | |
| Format: | Journal Article |
| Language: | English |
| Published: |
2023
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| Subjects: | |
| Online Access: | https://hdl.handle.net/10356/169024 |
| _version_ | 1826118171336114176 |
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| author | Tiwari, Satya Brat Hooper, Thomas J. N. Veksha, Andrei Chan, Wei Ping Fei, Xunchang Liu, Wen Lisak, Grzegorz Lim, Teik-Thye |
| author2 | School of Chemistry, Chemical Engineering and Biotechnology |
| author_facet | School of Chemistry, Chemical Engineering and Biotechnology Tiwari, Satya Brat Hooper, Thomas J. N. Veksha, Andrei Chan, Wei Ping Fei, Xunchang Liu, Wen Lisak, Grzegorz Lim, Teik-Thye |
| author_sort | Tiwari, Satya Brat |
| collection | NTU |
| description | Sewage sludge (SS) is a reclaimable phosphorus (P) source for fertilizer production, but it has a high toxic trace element (TE) concentration. Using alkaline leaching of SS, P can be extracted without simultaneous extraction of TEs. However, low P recovery efficiency during alkaline leaching is a major challenge. This study explored alkaline leaching of P from alum sludge (AS)-amended dry SS, with or without acidic pretreatment. The amendment with AS was intended to promote apatite to non-apatite inorganic phosphorus conversion for a higher alkaline P recovery. The highest orthophosphate (ortho-P) alkaline recovery was 74 % for the acid-pretreated SS + AS mix. Amending SS with AS averted the loss of ortho-P during acidic pretreatment by 59 % compared to the reference case (unamended SS). Standards Measurements and Testing (SMT) analysis revealed apatite to non-apatite inorganic phosphorus conversion during acidic pretreatment, especially in the amended SS. This conversion was due to the dissolution of Ca-P and adsorption of dissolved ortho-P on Al(OH)3 during acidic pretreatment. Visual MINTEQ modelling, solid-state NMR (31P, 27Al and 31P-1H CP-HETCOR) and Al 2p XPS data indicated a high abundance of Al(OH)3(s), which enhanced the ortho-P adsorption. There was no formation of AlPO4, possibly because the acid-sludge mixture reached the metastable equilibrium and not the true equilibrium during acidic pretreatment. 31P liquid NMR, SEM, FTIR and XRD provided additional insight into the effects of acidic pretreatment on sludges. Overall, Ca-P to Al-P conversion enhanced alkaline ortho-P recovery by about 12 % compared to the reference case (unamended + non-pretreated). This study demonstrated that P leaching efficiency from SS can be improved (with appropriate process modifications) irrespective of the intrinsic property of SS, thus making alkaline P recovery applicable in many regions globally. Additionally, the chemical co-treatment of SS + AS proposed is a prospective dual waste management strategy. |
| first_indexed | 2024-10-01T04:39:21Z |
| format | Journal Article |
| id | ntu-10356/169024 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2024-10-01T04:39:21Z |
| publishDate | 2023 |
| record_format | dspace |
| spelling | ntu-10356/1690242023-06-27T04:53:53Z Sequential wet extraction of phosphorus from sewage sludge using alum sludge: reassessing the aluminium-phosphorus speciation using experimental and simulation approach Tiwari, Satya Brat Hooper, Thomas J. N. Veksha, Andrei Chan, Wei Ping Fei, Xunchang Liu, Wen Lisak, Grzegorz Lim, Teik-Thye School of Chemistry, Chemical Engineering and Biotechnology School of Civil and Environmental Engineering Interdisciplinary Graduate School (IGS) School of Physical and Mathematical Sciences Residues and Resource Reclamation Centre Nanyang Environment and Water Research Institute Centre of High Field NMR Spectroscopy and Imaging Engineering::Chemical engineering Phosphorus Recovery Acid-Base Leaching Sewage sludge (SS) is a reclaimable phosphorus (P) source for fertilizer production, but it has a high toxic trace element (TE) concentration. Using alkaline leaching of SS, P can be extracted without simultaneous extraction of TEs. However, low P recovery efficiency during alkaline leaching is a major challenge. This study explored alkaline leaching of P from alum sludge (AS)-amended dry SS, with or without acidic pretreatment. The amendment with AS was intended to promote apatite to non-apatite inorganic phosphorus conversion for a higher alkaline P recovery. The highest orthophosphate (ortho-P) alkaline recovery was 74 % for the acid-pretreated SS + AS mix. Amending SS with AS averted the loss of ortho-P during acidic pretreatment by 59 % compared to the reference case (unamended SS). Standards Measurements and Testing (SMT) analysis revealed apatite to non-apatite inorganic phosphorus conversion during acidic pretreatment, especially in the amended SS. This conversion was due to the dissolution of Ca-P and adsorption of dissolved ortho-P on Al(OH)3 during acidic pretreatment. Visual MINTEQ modelling, solid-state NMR (31P, 27Al and 31P-1H CP-HETCOR) and Al 2p XPS data indicated a high abundance of Al(OH)3(s), which enhanced the ortho-P adsorption. There was no formation of AlPO4, possibly because the acid-sludge mixture reached the metastable equilibrium and not the true equilibrium during acidic pretreatment. 31P liquid NMR, SEM, FTIR and XRD provided additional insight into the effects of acidic pretreatment on sludges. Overall, Ca-P to Al-P conversion enhanced alkaline ortho-P recovery by about 12 % compared to the reference case (unamended + non-pretreated). This study demonstrated that P leaching efficiency from SS can be improved (with appropriate process modifications) irrespective of the intrinsic property of SS, thus making alkaline P recovery applicable in many regions globally. Additionally, the chemical co-treatment of SS + AS proposed is a prospective dual waste management strategy. Nanyang Technological University National Research Foundation (NRF) Public Utilities Board (PUB) This work was supported by the Nanyang Technological University (NTU) Singapore [#020472-00001, Environmental Sustainability Research Grant]. Satya Brat would like to thank NTU Singapore for his NTU Research Scholarship. This project was also supported by the National Research Foundation, Singapore, and PUB, Singapore’s National Water Agency under its RIE2025 Urban Solutions and Sustainability (USS) (Water) Centre of Excellence (CoE) Programme, awarded to NEWRI, NTU Singapore. 2023-06-27T04:53:53Z 2023-06-27T04:53:53Z 2023 Journal Article Tiwari, S. B., Hooper, T. J. N., Veksha, A., Chan, W. P., Fei, X., Liu, W., Lisak, G. & Lim, T. (2023). Sequential wet extraction of phosphorus from sewage sludge using alum sludge: reassessing the aluminium-phosphorus speciation using experimental and simulation approach. Chemical Engineering Journal, 459, 141569-. https://dx.doi.org/10.1016/j.cej.2023.141569 1385-8947 https://hdl.handle.net/10356/169024 10.1016/j.cej.2023.141569 2-s2.0-85147337445 459 141569 en 020472-00001 RIE2025 Chemical Engineering Journal © 2023 Elsevier B.V. All rights reserved. |
| spellingShingle | Engineering::Chemical engineering Phosphorus Recovery Acid-Base Leaching Tiwari, Satya Brat Hooper, Thomas J. N. Veksha, Andrei Chan, Wei Ping Fei, Xunchang Liu, Wen Lisak, Grzegorz Lim, Teik-Thye Sequential wet extraction of phosphorus from sewage sludge using alum sludge: reassessing the aluminium-phosphorus speciation using experimental and simulation approach |
| title | Sequential wet extraction of phosphorus from sewage sludge using alum sludge: reassessing the aluminium-phosphorus speciation using experimental and simulation approach |
| title_full | Sequential wet extraction of phosphorus from sewage sludge using alum sludge: reassessing the aluminium-phosphorus speciation using experimental and simulation approach |
| title_fullStr | Sequential wet extraction of phosphorus from sewage sludge using alum sludge: reassessing the aluminium-phosphorus speciation using experimental and simulation approach |
| title_full_unstemmed | Sequential wet extraction of phosphorus from sewage sludge using alum sludge: reassessing the aluminium-phosphorus speciation using experimental and simulation approach |
| title_short | Sequential wet extraction of phosphorus from sewage sludge using alum sludge: reassessing the aluminium-phosphorus speciation using experimental and simulation approach |
| title_sort | sequential wet extraction of phosphorus from sewage sludge using alum sludge reassessing the aluminium phosphorus speciation using experimental and simulation approach |
| topic | Engineering::Chemical engineering Phosphorus Recovery Acid-Base Leaching |
| url | https://hdl.handle.net/10356/169024 |
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